Protective device.



1. l. FRANK. PROTECTIVE DEVlCE. APPLlCATlON FILED OCT. 19. 1915.

atented July 1, 1916.

1 M1 m //n u/ a 4 inventor": John JFTank, 1% W 4 M His fittorneg.

,JOHN J. resumes Original application filed June 16, 1913,

UNITED STATES PATENT OFFICE.

PITTSFIELD, MASSACHUSETTS, ASSIGNOR TO GENERAL ELEGTRIC COMPANY, A CORPORATION OF NEW YORK.

PROTECTIVE DEVICE.

To all whom it may concern Be it known that I, JOHN J. FRANK, a

citizen of the United States, residing at Pit'tsfield, countyof Berkshire, State of Massachusetts, have invented certain new and useful Improvements in Protective Devices, of which the following is a specification..

The present application'is a division of my application, Serial No. 772,161, filed June 16, 1913.

My invention relates to protective devices for electrical installations, and in particular to devices for protecting electrical apparatus, such as transformers, included in a high voltage electrical transmission system.

More specifically, my inyention relates to that type of protective device described in the application for United States Letters Patent of Dr. Charles P. Steinmetz, filed June 19, 1913, SerialNo. 774,513.

The patent application above mentioned describes a protectiyedevice selective in its action and permitting a non-oscillatory flow of high frequency current coming from one i tion of the installation to be protected and toward the source high frethe other seereflects back quency disturbances arising in tion. I v

The object of my invention is to provide a novel construction and arrangement of apparatus particularly adapted to perform thefunctions of the protective device above described.

More generally, the ob ect of my invention is to provide a novel and compact ar- Specification of Letters Patent.

in the above mentioned patentrangement of inductive Winding anda noninductive winding in a single unitary structure. I

A further object of my invention is to pro-' vide a'nominductive resistance of novel and improved construction. The features of my invention which I believe to be novel and patentable are definitely indicated in the claims appended hereto. The constructionand arrangement of paratus in a protective device embodying the novel features of my invention will be understood from the following description taken in connection with the accompanying drawings, in which: I

Figure 1 is an elevation partly in section of a protective device embodying my invention, and Fig. 2 is av diagrammatic representation of my protective device operatively connected in an electrical installation.

Referring first to Fig. 2. of the drawings, it will be observed that my protective device is'arranged to protect the windings of .a transformer 5. This transformer is included in an electrical installation and has its high potential winding connected to transmission conductors 6. Translating de-' vices of any desired character may be connectecl to the transmission conductors 6; Such devices have been omitted in the drawings n order to simplify the showing.

An inductive winding 7 is included in series relation, with one of the transmission conductors, and this winding is shunted by a non-inductive resistance 8. The ohmic value of the non-inductive resistance 8 is approximately equal to the ohmic value of the surge resistance of the transformer 5. As explained in the hereinbefore mentioned patent application of Dr. Steinmetz, the ohmic value of the surge resistance of the transformer is equal to 3 where L and C represent in henries and farads the inductance and capacity respectively of the transformer. As the surge resistance of the transformer is many times greater than the surge resistance of the transmission conductors, the protective device comprising the inductance 7 and non-inductive resistance 8 will act to permit the non-oscillatory exit of any- PatentedJuly 1, 1916.

Serial No. 772,151. Divided and this application filed October 19,

1915. Serial No. 56,791.

inders 11.

the transformer and to reflect back. toward the source any high frequency disturbance arising without the transformer. It will of course be understood that I may insert a protective device in each transmission conductor if desired.

The resistance 8 should have 'substantia lly no inductance and to this end 1 have found it most desirable to employ a liquid resistance. The combination of a liquid resistance in a protective device of the type herein described, I consider to be an important feature of my invention. I have furthermore devised a novel construction of liquid rheostat which is peculiarly adapted to perform the functions of the resistance in the protective device to which my invention relates. The details of construction of this liquid rheostat will be understood from the following description.

In Fig. 1 of the drawings, I have illus-- trated a protective device of unitary construction embodying the inductance 7 and resistance 8 of Fig. 2. This protective device comprises a supporting base 10 of insulating material upon which are mounted concentric cylinders 11 also of insulating material. Preferably 1 construct the cylinders 11 of concrete or other stone-ware material. The inductance comprises a winding of bare copper wire 12, wound upon the cyl- The terminals of this inductive winding are indicated at 13 and 11 respectively. Porcelain sleeves 15 are mounted on the wire 12 and serve to space the turns of the winding from each other and also to space the wire conductors from the supporting cylinders.

A liquid containing vessel 16 is arranged within the inner cylinder 11 and rests upon the supporting base 10. This vessel contains a liquid electrolyte 17 which serves as the re sistance material of the liquid resistance. Preferably the electrolyte consists of a mix ture of 'ater. salt and gl cerin, the salt being added to obtain a certain ohmic value of the liquid. and the glycerin being added to prevent the mixture from freezing at low temperature. l

A tubular member 18 is mounted within thevessel 16 and serves to divide the electrolyte in the vessel into two portions. The bottom of the tubular member does not reach to the bottom of the vessel. and the electrolyte at the bottom of'the vessel therefore serves to electrically connect the portions of the electrolyte divide'dby'the tubular member. The vessel 16 and tubular member 18 are preferably of stone-ware material. The dielectric strength of this material is not, very great. and I have accordingly found it desirable to provide another insulating material between the twop rtions of electrolyte. This I accomplish by 1. roviding the tubular member with a double wall forming a liquid containing chamber. lnsir lating liquid 19, such as oil, is inserted in this chamber.

An electrode 20 is supported on inwardly projecting shoulders 25 near the top of the vessel 16 and extends into the electrolyte between the vessel and the tubular member. thus constitutine one terminal of the liquid resistance. This electrode is connected to the terminal 14 of the inductance by means of a conductor 21. An adjustable electrode 22 extends into the electrolyte. within the tubular member 18 and constitutes the other terminal of the liquid resistance. This electrode is adapted to be'connected to the terminal 13 of the inductance.

It will be seen that the tubular member 18 provides a plurality of paths for the flow of current through the electrolyte; If the cur-' rent is assumed to enter at the electrode it). it will flow downwardly in that portion of the electrolyte surrounding the tubular member to the bottom of'this member. and then upwardly through that portion of the electrolyte within the tubular member. The layer of insulating liquid supported by the double wall construction oi the tubular member insulates the portion of the electrolyte within the tubular member from the electrolyte surroumling the tubular member. except at the bottom of the tubular member where these two portions of electrolyte arc electrically connected.

The top of the vessel lh is closed by a cover of stone-ware material '2 The electrode 22 is sup].)orted by an insulating cap 21 which rests upon the cover 2 5. The upper portion .27 ot' the outer wall of the tubular member is of increased diameter and into the space between the two walls of this membe' a downwardly projecting ballle plate 2h extends. This plate is supported by the cover 23 and may be made integral therewith.

hat 1 claim as new and desire to secure by Letters Patent of the l nited States. is:'

1. A liquidresistance comprising in combination a liquid containing vessel. an elec trolyte within said vessel. means within said vessel for providing a plurality of electrically connected paths for the flow of current through said electrolyte and liquid insulating means for conlining the flow of current from one path to another to the point of electrical connection between the paths.

2. liquid resistance ctanprising in combination a liquid containing vessel. an electrolyte within said vessel. a layer of liquid insulating material suitably supported within said vessel and dividing the electrolyte therein into two electrically connected portions. and an electrode extending into each portion of said electrolyte.

3. A liquid resistance comprlsing in combination'a liquid containing vessel, an electrolyte within said vessel, an insulating layer of oil-suitably supported within said vessel and dividing the electrolyte therein into two electrically connected portions and an electrode extending intoeach portion of sulating material cooperating 'with said member for insulating said portions of elec-- trolyte. i v

5. A liquid resistance comprising in combination a liquid containing vessel, an electrolyte within said vessel, electrodes extending into said electrolyte near the surface thereof and constitutingterminals for said rheostat, means within said vessel for directing the flow of current from one electrode toward the bottom of said-vessel and thence toward the top of said vessel to said other electrode. and liquid insulating means for insulating the path of downward flow of the current from the path of upward flow of the current.

6.. A liquid resistance comprising in combination a liquid containing vessel, an electrolyte Within said vessel, a tubular member arranged within said vessel, an electrode extending Within said electrolyte between the vessel and the tubular member, a second electrode extending into the electrolyte within said tubular member, and liquid insulating material supported by said tubular memher for insulating the portion of the electrolyte within the tubular member from the electrolyte surrounding the tubular member.

7 A liquid resistance comprising in combination a liquid containing vessel, an electrolyte within said vessel, a tubular member having a surrounding liquid containing chamber mounted within said "essel, an in-' sulating liquid in said chamber, an electrode extending into the electrolyte between the vessel and the tubular member, and a second electrode arranged to extend into the electrolyte within said tubular member.

In witness whereof, I hay'ehereunto set my hand this 15th day of October, 1915.

JOHN J. FRANK. 

